Sewing machine



w. KOSTRO 2,655,885

SEWING MACHINE Oct. 20, 1953 Filed July 11, 1951 8 Sheets-Sheet l I l/ENTa E MLADYSLAW AQJTRO M WW/M Oct. 20, 1953 w KOS TRO SEWING MACHINE 8 Sheets-Sheet 3 Filed July 11, 1951 HHHHP ks u WW WH M 474/4- //VVENTOR WZADY5LAW K05TRO a FJ A TTOENEY Oct. 20, 1953 Fileci July 11, 1951 W. KOSTRO SEWING MACHINE 8 Sheets-Sheet 4 "wen/70K WA A DYSLA W KOSTRO 21 M ,1 T ToRA/FY w. KOSTRO SEWING MACHINE J Oct. 20, 1953 Filed July 11, 1951 8 Sheets-Sheet 5 jNuE/QTOE wLAbysLAw KOSTEo Oct. 20, 1953 w KOSTRQ 2,655,885

I SEWING MACHINE V Filed July 11, 1951 v 8 Sheets-Sheet 6 J ZIaJQ.

WLADYSI-RW KOSTRO A l/9m 2 y INVENToR I Oct, 20, 1953 w, K R 2,655,885

SEWING MACHINE Filed July 11, 1951 8 She ets-Sheet 7 INYE Nifok wLHDYSLAw KoST'Ro I Oct. 20, 1953 w. KosTRo 2,655,885

SEWING MACHINE Filed July 11, 1951 8 Sheets-Sheet 8 flwznv'ok WI-HPYSLAW kosmo BY A Patented Oct. 20, 1953 SEWING MACHINE Wladyslaw Kostro, Kensington, London, England, assignor of one-half to Stanislaw J ozwiak, London, England; Roman Dabrowski, executor of said Wladyslaw Kostro, deceased Application July 11, 1951, Serial No. 236,117 In Great Britain October 18, 1949 2 Claims. (Cl. 112-7) This invention relates to sewing machines and has for its object to provide an improved form of sewing machine which is capable of sewing together abutting edges, such as the edges of strips of carpets or the edges presented by a tear in material so that the stitches are visible only on one side and cannot be seen from the other side which would normally constitute the outer side of the material. Alternatively, the machine is capable of sewing together two or more layers of material in such a manner that the stitching penetrates through all of the layers with the exception of an outermost or lowermost layer, the stitching only penetrating through a portion of the thickness of this outer or lowermost layer so as not to be visible on the other side.

Although the machine in accordance with the present invention is primarily intended to stitch together materials so that the stitching is not visible on one of the sides, it can nevertheless be used in instances where it is desirable that the stitching should extend completely through the material so as to be visible on both of the exposed surfaces.

According to the present invention there is provided a sewing machine which comprises a semicircular hollow needle which is pointed at its outer end and formed with an eye adjacent to the point through which the thread leaves the needle after passing therethrough from a source of supply, means for imparting oscillatory movement to the needle, a member for receiving a second thread, means for imparting synchronised oscillatory movement to said member to move the member in a plane at an angle to the plane of the needle to efiect a stitch forming operation, a base, means for supporting the needle and the member for the second thread adjacent to said base, said base having an opening through which the needle can move to penetrate through, or penetrate to a predetermined depth a thickness of material being sewn and upon which the machine rests, and to emerge from the surface of the material at which the needle entered and thus present above the said surface a loop for co-operating with said member for the second thread for stitch formation, and means for effecting intermittent step by step movement of the machine over the workpiece between stitch forming operations.

The construction and operation of the machine may be such as to produce a lock stitch or alternatively a chain stitch or a double chain stitch.

Any suitable means may be employed for imparting the required oscillatory movement of the looper (or bobbin) and needle.

The invention also provides means for efiecting intermittent step by step movement of the machine over the workpiece during or between stitch forming operations and this movement can be effected when the workpiece is lying flat on a supporting surface due to the fact that the needle need not necessarily pass right through the material to the other side thereof.

In order that the invention may be clearly understood and readily carried into effect, embodiments thereof will now be described by way of example with reference to the accompanying drawings. In the drawings:

Figure 1 is a perspective view from the front and one side of a machine for a sewing together the edges of strips of carpeting,

Figure 2 is a rear perspective View of Figure 1,

Figure 3 is an inverted fragmentary plan view, drawn to a larger scale, of the bobbin and needle mechanism,

Figure 4 is an inverted plan view of the bobbin casing,

Figure 5 is a vertical section taken on the line V--V, Figure 4,

Figure 6 is a vertical section of the bobbin casing looking in the direction of the arrow VI of Figure 4 but showing the bobbin in elevation,

Figure '7 is a greatly magnified sectional view of the needle,

Figure 8 is a detail perspective view showing how a sling of thread formed by the needle is picked up by the bobbin casing prior to being wound round the bobbin thread,

Figure 9 is a diagrammatic plan view showing the form of stitch produced when sewing together the edges of carpeting,

Figures 10 to 13 are diagrammatic inverted plan views showing different positions of the bobbin casing when oscillated through a complete cycle of operations,

Figure 14 is a section taken on the line XIV-XIV of Figure 11,

' Figures 10A to 13A are diagrammatic views which correspond respectively with Figures 10 to 13 inclusive and illustrate the movement of the needle and the looping of the needle thread around the bobbin thread,

Figure 15 is a perspective view of a machine similar to that shown in Figures 1 and 2 but which is designed for sewing together two or more thicknesses of material,

Figure 16 is a diagrammatic view showing the 3 form and stitch produced with the machine illustrated in Figure 15,

Figures 17 to 23 are purely diagrammatic views which illustrate respectively consecutive stitch forming operations performed by a modified form of mechanism embodying a needle and looper, Figures 17 and 20 being front views of the parts and the remaining figures plan views,

Figure 24 is a View showing the resultant, stitch, and

Figures 25, 26 and 27 are fragmentary views showing details of construction.

Referring firstly to Figures 1 and 2 of the drawings, the machine is rested on two strips or pieces of carpet which are required to be sewn together along abutting edges so that the needle mechanism I and bobbin mechanism '2 are disposed respectively one on each side of the abutted together edges of the carpeting, the needle mechanism being fitted with a depending feeler member which engages between the edges of the pieces of carpet and ensures that the edges are correctly positioned as the sewing operation takes place.

The bobbin mechanism comprises a bobbin casing 3 which is oscillated, normally in a horizontal plane, through about 330 in both clockwise and anti-clockwise directions. The needle mechanism I comprises a needle housing 4 supporting a hollow needle of semi-circular shape as shown in Figure 7 and which will be described in detail hereinafter. This needle is oscillated in a vertical plane in synchroni-sm with the oscillation of the bobbin casing so that during each stitch forming action, the needle thread, after being passed through the material, is offered to the bobbin mechani m and is carried around by the latter so as to twist the needle thread around the bobbin.

This embodiment of the invention concerns essentially the provision of an oscillatable bobbin casing and a complementary oscillating needle and it will be readily appreciated that many different kinds of mechanism may be employed for effecting the oscillation of these parts. The mechanism illustrated in Figures 1 and 2 is a preferred form and will be described more fully in detail hereinafter.

Referring next to Figures 4, 5 and 6, the bobbin casing 3 comprises two co-axial halves 5 and B which are each of dish-like form and arranged with their circumferential flanges 5a and 6a spaced slightly apart and which slide respec-. tively during oscillation of the casing, one on each side of a ledge in a hole formed in a main base plate 1 of the apparatus.

The bobbin 8 is located between the halves 5 and 6 of the casing and these halves are detachably connected together by means of a pin '9 fitted at one end with a screw head In and "at the other end with a transverse locking pin "II which is passed through a slot I! in the centre of the part 6 and the pin turned slightly to'bridge the slot. A compression spring I3 is provided in a hollow hub-like part 51) of the part 5 so that its tendency is to urge the twoparts slightly away from one another and so ensure that the locking pin 9 abuts tightly against the part 6.

The thread from the bobbin 8 is withdrawn through an angular slot I4 in .a separate ringlike part 82) forming the peripheral wall of the bobbin and is threaded through a borein a tube like part through which it is released from the bobbin and permitted to pass to the top of the material which is being sewn. Withwith teeth l8 which are engaged by two coplanar small gears iBa (see Figure 25) on which are superimposed still smaller gears l9b actuated by a main gear [9 which is oscillated backwards and forwards to effect corresponding oscillation of the bobbin casing. Although the ring-like part 3b is permitted slight turning movement through a few degrees, it can be regarded as stationary with respect to the casing 3 and the bobbin 8 is also held against movement with the casing 3 but can be turned slowly to permit the thread to be unwound.

Dealing next with the mechanism which is shown clearly in Figure 7, the needle comprises a tube which is semi-circular or approximately semi-circular in shape. This tube has a fine bore 2 I, through which thread or cotton 22, from a reel 23, is passed by way of various looped tensioning devices, the outer end of this tubular needle 29 being cut obliquely and sharpened into a point 24 and being formed just in front of the point 24 with a hole 25 through which the thread 22 passes.

The needle 25! is supported to oscillate in a vertical plane at right angles to the plane of the bobbin and is supported atone end by a block or arm 25, mounted on a spindle 27 (Figures 3 and '7) which is actuated by a gear 28 meshing with a larger gear .29 which is rocked by a link 30 acted on by further linkage 3! (Figure 1) having a lateral projection which engages in a cam groove 32 in a disc 33 carried at one end of a shaft 34 (Figure 2) having a bevel gear 35 driven by a second bevel gear 35 mounted on a driving shaft 3! which is driven at its upper end by an electric motor 3'ia (see Figure 26).

A cycle of operations will now be described with reference to Figures 10 to 13 read in conjunction with Figures 10A to 13A. Figures l0 and 10A show the positions of the bobbin casing 3 and the needle at the end of a stitch forming operation when the needle thread has been looped around the bobbin thread and main tensioning means referred to later, actuated to take up the slack in the needle thread which has to be, permitted during the looping operation. In this position the needle H! is withdrawn and the bobbin casing 3 has to be turned in a clockwise direction to the position shown in Figure 11. The flanges 5a and 6a of the complementary parts 5 and 6 of the bobbin casing are each formed with an arcuate cut away portion 38, which open at the peripheries of the flanges 39 so as to constitute a hook or claw. Thus each part 5 and 6 of the bobbin casing comprises a claw 4i? and the two claws 46 of the parts 5 and 6 are aligned so that in effect they provide a single claw comprising two prongs as shown clearly in Figure 8. The annular toothed ring I1 is interrupted at the claws so as to leave a space into which the needle can pass when it is oscillated. When the bobbin reaches the position of Figure 11, the needle, which moves in synohronism with the bobbin, has penetrated a part of the thickness of the material and passes out of the upper surface of the material and then into the space 38 inside the claws '40 as shown in Figure 11A. The bobbin casing now commences to move just prior to the insertion of the needle to ensure that the needle thread sling is positioned for engagement by the claws 40.

The needle thread 22 is stretched across the needle as shown in Figure 8 to form the sling and the needle is then held stationary momentarily until the sling is engaged by the prongs 4i] of the bobbin casing which is now moving in the opposite direction. Immediately the needle thread has been caught up by these claws 40, the needle 28 is moved clear of the claws 40, as movement of the bobbin casing is continued but in said anti-clockwise or opposite direction which results in the needle thread being carried around the under surface of the bobbin casing 3 as shown in Figure 12, in which it is looped around the bobbin thread. The needle thread 22 is pulled through the needle 20 to permit sufficient slack of needle thread to be obtained as the latter is stretched across approximately the full diameter of the bobbin casing 3, the chain dotted position of the thread 22 showing the thread just before what may be termed a dead centre position is reached and the full line position of the thread indicates the position after said dead centre has been passed and the needle thread is about to slip down the space 33 between the claws 39 so that when the bobbin reaches the position shown in Figure 13 the needle thread automatically falls out of said slot to form a complete loop about the bobbin thread which is pulled out through said short tube !5 so that the bobbin thread is held tight against the upper surface of the material being sewn. In actual practice of course, the needle thread does. not fall from the space 38 between the claws but is pulled therefrom automatically by the main tensioning mechanism which is brought into operation at this stage to take up the slack in the needle thread 22 ready for subsequent operation. The position of the bobbin casing inFigure 13 is now the same as that in Figure 10 when the commencement of a cycle of operations takes place.

The ring like part 8b of the bobbin is frictional ly supported in the bobbin casing so that it is moved with the casing only for a few degrees when the casing 3 is turned in opposite directions. This enables the short tube E5 to move from the position of Figure 11 to the position of Figure 12 and vice versa, this movement facilitating easy withdrawal of the bobbin thread than would be possible if the tube were held rigid and immovable and also permitting the loop of the needle thread to move over the end of the tube (which will yield slightly) to permit the needle loop to be tightened about the bobbin thread.

In Figure 9, two fragments ll and 42 of the carpet are shown butted together edge to edge. The bobbin thread 53 is shown stitched by the needle thread 22 against what will normally be the underside of the part ll of the carpet and the needle thread 22 will also be visible on both the undersurfaces of the carpet 32. The portion of the needle thread which penetrates the thickness of the carpeting however, remains concealed and will not be visible from the top surface of the two pieces of carpet when they are arranged uppermost so that the stitching connecting the two pieces of carpet remains invisible. In effect, two lines of stitches are formed which are positioned respectively one on each sides of the abutting edges 4| and 42, one of the lines being formed by the thread d3 of the bobbin being tightened by the sling of the needle thread 6 22 and the other by the thread of the needle as it penetrates into the material from above to join the stitches.

As previously explained, any suitable form of mechanism may be employed for operating the bobbin and needle mechanisms in synchronism. In Figures 1 and 2 of the drawings, the machine is normally provided with a bridge 31b (Figure 26) for supporting the motor 21a which drives the upper end of a shaft 31 by way of a suitable clutch mechanism 310. This shaft 31 in addition to supporting the bevel gear 36, for transmitting the drive to the needle 20, also supports a disc 44 which is formed in its upper surface with a cam groove 45 in which engages a depending pin 46 provided at one end of a bell crank lever 41 which is pivoted at 48, the other end of this bell crank lever d'l actuating a link 49 which in turn operates a link 50 which is oscillated to swing a main tensioning device 5| which is movable in one direction to take up the slack in the needle thread 22 at the end of a stitch forming operation and in an opposite direction during a stitch forming operation when said slack is required.

The disc 44 also comprises upper and lower parts between which is supported one end of an arm 52 which is eccentrically mounted so that the arm 52 is reciprocated after the fashion of a piston rod as the disc 44 is rotated, the outer end of this arm 52 being connected to one end of a link 53 which is pivotally anchored at its other end to a bridging plate 54. Ihe link 53 is fitted with a depending pin 55, which enters an arcuate slot 55 in the gear 19 already referred to so that as the arm 52 is reciprocated, the gear I9 is oscillated to effect driving of the bobbin casing 3 by way of the two small co-planar gears which mesh with the gear It on the bobbin casing. The pin and slot action 55-56 gives the required momentarily stationary condition of the bobbin casing 3 during the positioning of the needle thread sling in the path of the claws, and additionally this pin and slot connection allows the bobbin casing to remain stationary momentarily as the needle loop passes from the short tube 15 and is tightened about the bobbin thread.

The rear end of the machine is fitted with a pivoted skid 51 which rides smoothly over the material being sewn.

As stated, the movement of the needle is controlled by the cam groove 32 in the disc 33 and the shape of this groove is such that it retains the needle momentarily stationary as the needle sling is being engaged by the claws 40 and again when the bobbin casing is being returned in an anti-clockwise direction during looping of the needle thread about the bobbin thread. At the actual moment of tightening of theneedle loop about the bobbin thread, both needle and bobbin casing are stationary.

The movement of the arm 52 is such that the main gear i9 is moved at different speeds so that the bobbin casing moves slowly as it picks up the needle sling and then moves quickly.

When threading the needle 20, the thread from the reel 23 is passed around a tensioning element 5! and is then engaged in the loops of a looped wire 23a and then through the end of the needle carried by the block as as shown in Figure 8.

It is preferred that the machine shall advance step by step intermittently and automatically over the material between the stitch forming operations, and for this reason, the rear end of the machine is fitted with two wheels 5% which pass through aligned slots in the base plate 'i and the skid '1 and rest directly on the material, the eri heral edges of'these wheel's being milled, serrated or otherwise suitably roughened so as to engage positively with th'ematerial. Preferably, the wheels '58 are each independently sprung by means of a spring contained in a housing 59 at each end of a shaft EU for supporting the wheels. This shaft fit is fitte'd with a one-Way drive mechanism 5| which is actuated at the end of each stitch forming operation by one en-d of an arm '52 which is actuated att-he appropriate moment by a cam 6212 on the disc 4'4 engaging and depressing a roller carried by the arm 62., the roller (not visible) beingmounted on a "pin 62c.

The length of a stitch can be varied by means of a regulating devicetfi-a acting on the'arm 62 which controls forward movementbf the mach-ine between stitch forming operations. The member E E-a is a screw which can-be adjusted toact on the arm 52 to allow said arm to rise or fall to control its swinging movement so that the arm 62' can turn the free wheel device- M toa greater or less extent and accordingly cont-relthe degrees through which the wheels 53 are turned.

Figure 15 illustrates a modified form of machine which is intended to stitch together two or more superimposed layers of "fabric, preferably, although not essentially so that the-stitching is only visible from one-side of the composite layers. The bobbin mechanism 3 and needle mechanism 3 is "substantially the same as that previously described but in the present-case, the bobbin mechanism follows along' the line immediately behind "the needle mechanism instead of moving alongside or abreast the ne'edie mechani'sm as in the foregoing embodiment. This embodiment illustrates clearly -a presser ioo't which is adjustable for height so that the-depth 'of penetration or" the needle 28 through the' lewermost layer 'can'b'e adjusted. The stitch "produced by the 'inacnine of Figure 15 is sim ila-r totha't produced by the carpeting machine, only in this icase, the needle thread "22 i's'drawn up tightly :as it does not have to spanthe two edges of the carpet. The machine is moved forward inte'rin'ittently say by one eighth "of an inch so that the-thread of the next-stitch crosses the thread of the' foregoing stitch. In this case, the machine forms -achain of cross stitches making -sim1ilt'aneeus'ly two stitches of which one is following theother by a distance ofthree eiehths' ofan inch. Qne' stitch is formed by the thread d3 of the bohbi-n 'being tightened by the needle thread and the-other stitch by theneedle thread '22 ti'glitening "in the enclosed or penetrated material. anechamer stitches forms two close lines of stitches which are 'visilil'e on the to of the material-only, the stitches on the inside of the material forniingla pattern of crossed threads. The *form of stit'ch is illustrated clearly in Figure 16 in' which only a single thickness 01 *mat'eria1 "is shown to avoid division lines between the thicknesses dime-serial passing through the stitch lines.

The driving mechanism for this machine comprises an electric motor 31a which is carried by a bridge or saddle 37B -(see'-Figu1-'e2-7-) and which drives down on to a pulley 6'4 mounted on a spindle fitted with a worm '55 which drive-s' 'a worm shell 68 mounted on a spindle for'driving the main disc 4 This disc d tg'as previously, is formed in its upper face with a cam groove 45 which actua'tes links Ma, Ma, and-58a, to swing a main tensioning device 5 t for the :n'eedleithread 22. Inthisdasa the gear l9 is fitted an' upstand- 13 which .is fitted at its upper end "with a .l'aterally directed pin-which engages in a cam groove 'ls 'tltted" with a sharp step which efi'ects a sudden and rapid swinging movement of the :bellcrank lever 7'3 and imparts reciprocatory movement to the arm 12. This machine is fitted witha single wheel E'Bi-or engaging thematenialand this-Wheel is suitably driven intermittently sat athe end :of each st'ltch forming operation Ito advance the machrr-ie automaticauyi by :a distance correspondingtothe lengthof a sti-tch. emeansisprovid'ed for regulating the length oer-stitch.

With another embodiment-not illustrated, the machine is actuated-by and comprises'a handle which is inclined upwardly and "which is adapted to be depressed tcwardslthe base plate] and which moves away: from the latter under the influence of spring means. -'I his lever :actuat'es a-train' o'fsmall-gearwheels which impart oscillatc'ry movement :toflthe horizontally disposed bobbin casing via its gear $8 and :at :the "same time -'rec iprocates rack members which engage with small gearwheelsat each end-"of the needle axle 2? so as to osc'illate the said axle to produce thenecessaryoscillatory-movement of the needle.

"intermittent increment d? the appliance along the material may be efiectsd by: arranging that on the return stroke of th'eoperating handle partial rotation is imparted to wheels lWhiCh-'COI1- tact thesurface-of thernaterial.

instead of arranging ior-zthemechanism to .be operated icy-the up and' down movement :of :an operating handle, the mectianism' -can Lbe .operated in rotating a harrdaw heel.

Although "it is preferred and conveni'ent to arrange for the machine to travel over ithezmateri'al 'bo'ing sew-n, the niatihinfimay :b'e hel'd 'stationary and the material i'ed under the machine so as to be acted upon by the latter.

"Referring lastly to'Figu-res l' 7 to 2e of the drawings, whichillustrate annarrangement in which a looper'is used instead of a bobbin-the needle isindicated at 1'5 and the'lo'oper at throughout t-he-variousviews. The looperamay be of any suitable known design :and :com'prises a hollow-portion through which threadztrom a :reel ltd is passed, so as to extend fromithe free .end thereof.

The ne'el-le 75, astl'escribed in the prior .embodiments, is hollow -and of circular or substantially semicircular shape as shown and may conveniently comprise a tube having a fine bore throug'bwhi'ch thread from a reel '11 is passed by way .ofwa'rious "looped Wire 'tensionindevices, lthe outer end of the needle -being cut obliquely and 'sharpened'iinto a point and "being formed .just iniront of the point with a hole through which the thread passes.

Theneedle 554s oscillated in a vertical ,plane in-synchronism with oscillatory movement aim- .parted to ithe :looper :76 which is disposed in a horizontal plane at right angles to the .plane of :the needle '15 so that cluning's'titch forming operations, the needle :and :loopercthreads, which are :indicated generallyzat slit and z'lemespectively are interlooped to form a chain stitch in a manner about to be described.

The sequence of stitch forming operations performed by the needle 15 and the looper '56 are as follows:

As the stitch forming operation commences (see Figure 17) the needle 15 penetrates the material and as it ascends it forms a loop 8| above the material. The needle 15 then remains stationary momentarily and the looper "it enters the loop Bl of the needle thread as shown in Fig. 18.

The needle then moves back to its starting position as shown in Figure 19 and leaves a loop 82 of its thread round the looper 16 and the machine then moves one stitch length forward so that the loop 82 assumes the position indicated in dotted lines in Figure 2 As shown in this figure, the needle 15 again moves to carry its thread through the material 60 and as it ascends its point passes through a loop 83 formed in the thread i9 of the looper 16.

The needle then remains stationary momentarily whilst the looper '56 as shown in Figure 21, moves back to its starting position and overloops the needle 15 with its thread as indicated at 8 2. During this movement, of the looper 16, it also draws its thread through the loop 82 previously formed in the needle thread E8.

With the needle still remaining stationary, the looper '16, as shown in Figure 22, again moves forwardly and enters a further loop 8-! (not visible) formed in the needle thread 18 during the last or second mentioned movement of the nee dle 15 through the material and, as shown in Figure 23, the needle again moves back to its starting position leaving another loop of needle thread around the looper 16 and the machine then moves one stitch length forward and the stitch forming operation described with reference to Figures 17 to 23 of the drawings is repeated to produce the line of stitching.

The stitch formed is a double chain stitch or double lock stitch as shown in Figure 24.

Any suitable means may be employed for imparting the desired synchronous movement to the needle and the looper. The means for operating the needle may for example, be either of the two mechanisms already described, with reference to Figures 1 and 2, or Figure 15 of the drawings, but with the present embodiment only a little excess needle thread has to be taken up.

Intermittent movement of the machine over the material being sewn may be effected by the same mechanism as that already described although alternatively the machine can be held stationary and the material fed under the machine.

I claim:

1. A sewing machine for sewing together abutting edges of material such as strips of carpet, comprising a semi-circular hollow needle which is pointed at its outer end and formed with an eye adjacent to the point through which the thread leaves the needle after passing therethrough from a source of supply, means for supporting and oscillating the needle in a vertical plane transversely to the direction of travel of the machine, a base, said base having an opening through which the needle can move and penetrate the edges of both the materials to be sewn together, a bobbin casing supported in a horizontal plane alongside the needle at one side of the edges to be joined together, means for imparting oscillatory movement to the bobbin, means on the bobbin casing for catching a loop in the needle thread after the needle emerges from that surface of the material at which the needle entered to loop the thread from the needle about a thread emerging from the bobbin in said casing for stitch formation, a skid carried by the base at the rear thereof, vertically disposed wheels carried by a shaft on said base and extending through slots in the base and said skid to contact the surface of a workpiece, a oneway drive mechanism fitted to said shaft, and means for automatically actuating said one-way drive at the end of a stitch forming operation to effect intermittent movement of the machine between stitch forming operations.

2. A sewing machine comprising a semi-circular hollow needle which is pointed at its outer end and formed with an eye adjacent to the point through which the thread leaves the needle after passing therethrough from a source of supply, means for supporting and oscillating the needle in a vertical plane, a base, said base having an opening through which the needle can pass to penetrate material upon which the machine rests, a bobbin casing supported in a horizontal plane by said base, said bobbin casing comprising two complementary dish-like halves between which the bobbin is supported and retained, the flange of each of said halves being formed with an arcuate cutaway portion which opens into the periphery of the flange to form a claw, the claw of one part of the bobbin casing being aligned with the claw of the other half to form the hook which coacts with the needle thread, means for imparting oscillatory movement to the bobbin, casing means for guiding the bobbin thread to the workpiece, a hook on the bobbin casing for catching a loop in the needle thread after the needle emerges from that surface of the material at which the needle entered to loop the thread from the needle about a thread from a bobbin in said casing for stitch formation, and means for effecting automatic intermittent step by step movement of the machine over the workpiece between stitch forming operations.

WLADYSLAW KOS'I'RO.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,050,595 Arbetter Jan. 14, 1913 1,119,561 Zahn Dec. 1, 1914 1,176,415 Whitelaw Mar. 21, 1916 2,075,656 Paternayan Mar. 30, 1937 2,544,263 Hohmann Mar. 6, 1951 2,575,327 Ashley et a1. Nov. 20, 1951 FOREIGN PATENTS Number Country Date 136,133 Austria Jan. 10, 1934 956.126 France July 11, 1949 

